Anyone who imagines that there is some mythical "code of honor" on any field of combat is living in a fantasy world. You don't go to battle with the intent of "playing fair". You go into it with the intent of winning the battle through whatever means possible. If that means taking advantage of an enemy's stupidity (like sleeping during the day, or leaving their officers unprotected) then you damn well do that and worry about the war crimes tribunal if your side loses, later.